It was just a year ago that another title was added to the swiftly growing collection of ‘science for the layman’. The book Move:The New Science of Body Over Mind by Caroline Williams begins with a hilarious but relatable anecdote. The author had walked into a dance club and was expected to let her limbs loose. She had to sway to the lively music, allowing the rhythm to overpower her senses and command her moves. The result was not particularly surprising. After an hour of wild dancing, the author learned to appreciate the upside of moving without restraints, and understood how rhythm can induce the brain to follow the beat.
Most humans in the world instinctively enjoy the enthralling vigour of musical rhythm and appreciate as well as benefit from its therapeutic qualities. Rhythm is characterised by a pattern of sounds that repeats over and over again. And identifying such a pattern requires a set of cognitive abilities which are possibly unique to humans. Thus, another behaviour human beings can solely demonstrate is the production of rhythm, and this gives them an edge over animals. Like producing words which are strung together to convey meaningful messages, humans are exceptional at feeling the beat. Or so it was believed, until a recent study proved the belief wrong.
A look at the ‘singing primates’ of Madagascar would help clarify why. The indris (Indri indri) are a kind of lemur that feed on leaves. But there is something curious about these tree-dwelling primates. They communicate using vocalisations and Indri songs have rhythmic categories akin to those present in human music. Apparently, humans are not the only living beings that can produce rhythmic patterns. As researchers observed, the songs produced by the indris are marked by categorical rhythm, which is present in various human cultures that create music. Categorical rhythm implies that two sounds are separated by exactly the same duration or by a doubled duration. It helps to recognise a song without difficulty, though the song might be sung at different speeds. Humanity may have a gift for producing rhythm but there is someone it needs to share the stage with.
Studying the songs of various species such as the critically endangered Indris sheds light on our own evolutionary past. Andrea Ravignani, a researcher in the field of evolutionary biology, talks of the importance of constructing an ‘evolutionary tree’ of musical traits. This can be done by looking for musical features in species other than humans. The evolutionary tree would ultimately help one understand how rhythm and musicality evolved in human beings. The songs of the Indris share another commonality with human music. They are characterised by a ‘ritardando’, which is a term used to refer to the eventual ‘slowing down’ native to many musical traditions around the world. But the origin of the rhythm which is familiar to both humans and indris might not have been the same, as the last common ancestor of humans and the indris lived 77.5 million years ago. Instead, it is suggested that the ability to produce categorical rhythms evolved independently among species that sing, such as the indris. Moreover, this ability does not overlap with or share any link to the human ability to produce rhythm. The indris use their sense of rhythm to sing mellifluously. But could humans have taken their understanding of rhythm a step ahead?
The origins of human language are debatable, but the few reliable guesses do seem convincing enough. Mario Vaneechoutte and his students suggested that language emerged from music. This can act as a foolproof evidence to the fact that language and rhythm are closely connected. Evolution, if not humans, surely cashed on the human ability to produce rhythmic sounds, leading to, as this theory suggests, complex language. Musical rhythm might have been one of the stepping stones to language but it is unclear when language actually evolved.
But language does not ‘fossilise’ which is why we can only speculate. Could another species related to modern humans (Homo sapiens) speak? Were the Neanderthals capable of producing human-like language? A study answered in the positive. A group of researchers created virtual 3D models of the structures of the ears of both Homo sapiens and Homo neanderthalensis. Using these, they could estimate the hearing frequencies of each species. They discovered that Neanderthals could hear sounds of frequencies similar to those humans can hear, which may provide us with a reason to believe that Neanderthals could speak. Language is not only about speaking, but it involves several rudimentary skills such as listening, and, in the modern world, reading and writing. The assumption is that a creature capable of hearing the sounds of human language might also have been able to produce sounds similar to those of human language. If this is indeed true, we were perhaps never really far ahead of our heavily-built, thick-browed cousins.
Language is about sounds, and sounds which are placed in a pattern with a relatively uniform gap, create rhythm. If there is something that links language to music, it is indubitably rhythm. And poetry is an epitome of rhythmic language. Rhythm helps us grasp the message conveyed by a poem better. The English word ‘rhythm’ is derived from a Greek word which means ‘flow’. A poem represents an unrestrained flow of thoughts, cascading down the page in wonderful rhythmic patterns. Together, poetry and music sum up the essence of being human, explaining how language and rhythm are inherent to as well as products of the human psyche.
Rhythm is universal, as dogs, parrots, and chimpanzees respond to it, and the indris use it too. But what perhaps is still blocked from sight is why any creature learnt to recognise rhythm at all or why rhythm processing entered the endless flow of evolution.
Vallari Soman
